add initial marp implementation with sample content and build configuration

node_modules/@marp-team/marpit/lib/helpers/wrap_array.js

@@ -0,0 +1,21 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.wrapArray = exports.default = void 0;
+/** @module */
+/**
+ * Wrap value in array if it is not an array.
+ *
+ * @function wrapArray
+ * @param  {*} valOrArr
+ * @return {Array}
+ */
+const wrapArray = valOrArr => {
+  if (valOrArr == null || valOrArr === false) return [];
+  if (valOrArr instanceof Array) return valOrArr;
+  return [valOrArr];
+};
+exports.wrapArray = wrapArray;
+var _default = exports.default = wrapArray;